The present application claims the priorities of the commonly owned copending German patent applications Nos. 101 40 309.7 (filed Aug. 16, 2001) and 101 54 807.9 (filed Nov. 8, 2001). The disclosures of the above-referenced German patent applications, as well as those of each US and foreign patent and patent application identified in the specification of the present application, are incorporated herein by reference.
The present invention relates to improvements in machines for making cigarettes, cigars, cigarillos and other smokers"" products, particularly smokers"" products of the type wherein a rod-like filler of smokable material is confined in a tubular wrapper of cigarette paper or the like. More particularly, the invention relates to improvements in apparatus for treating smokable material, such as a mixture of randomly distributed shredded tobacco leaf laminae (hereinafter called shreds and constituting the higher-quality fraction of comminuted tobacco leaves) and comminuted tobacco ribs, eyes and the like (hereinafter called ribs and constituting the less desirable fraction of comminuted tobacco leaves), prior to the making of the filler.
As a rule, the so-called distributor or hopper of a cigarette making machine receives batches of intermixed tobacco shreds and tobacco ribs and converts such batches into one or more streams or flows which consist primarily or mainly of shreds and contain more tobacco than necessary in a rod-like filler which is ready to be confined in a wrapper. The stream or streams is or are gathered on and are advanced by one or more foraminous belt conveyors which advances or ad-advance the stream(s) past one or more trimming or equalizing devices serving to remove the surplus. Each of thus trimmed streams or fillers is fed into a discrete wrapping mechanism which drapes the single trimmed filler or the respective trimmed filler into a running strip or web of wrapping material. Each of the thus obtained cigarette rods is severed to yield a sequence or file of discrete plain cigarettes of unit length or multiple unit length, and such cigarettes are fed into a packing machine or into a so-called tipping machine wherein the cigarettes (normally of multiple unit length) are united with filter mouthpieces of unit length or multiple unit length to form therewith filter cigarettes of unit length or multiple unit length.
The apparatus of the present invention is designed to treat a mixture of tobacco ribs and tobacco shreds in the distributor or hopper of a cigarette making, cigar making, cigarillo making or an analogous machine prior to conversion of the mixture into one or more streams which are fed to the trimming or equalizing device(s). As a rule, the mixture which enters into and moves in the distributor is treated and advanced by air in conjunction with implements and/or groups of implements including rotary brushes, so-called picker rollers, carded rollers, ducts, belt conveyors, plate-like guides, suction chambers, nozzles and the like. Reference may be had, for example, to commonly owned U.S. Pat. No. 5,645,086 granted Jul. 8, 1997 to Brand et al. for xe2x80x9cAPPARATUS FOR EVACUATING SURPLUS AIR FOR (sic!) THE DISTRIBUTOR OF A TOBACCO PROCESSING MACHINExe2x80x9d. The manner in which one or more streams of smokable particles are treated after it issues or they issue from the distributor, and in which the trimmed off surplus is returned into the distributor, is disclosed, for example, in commonly owned U.S. Pat. No. 5,072,742 granted Dec. 17, 1991 to Heitmann for xe2x80x9cMETHOD OF AND APPARATUS FOR MAKING A FILLER OF SMOKABLE MATERIALxe2x80x9d. Commonly owned U.S. Pat. No. 5,526,826 (granted Jun. 18, 1996 to Heitmann for xe2x80x9cAPPARATUS FOR REMOVING SURPLUS FROM A TOBACCO STREAMxe2x80x9d) discloses one presently preferred trimming or surplus removing device which converts a surplus-containing stream of tobacco particles into a rod-like filler which is ready to be draped into a continuous strip or web of cigarette paper or the like. A cigarette making machine with means for simultaneously trimming two streams of tobacco particles issuing from a distributor is disclosed, for example, in commonly owned U.S. Pat. No. 4,893,640 granted Jan. 16, 1990 to Heitmann et al. for xe2x80x9cMULTIPLE-ROD CIGARETTE MAKING MACHINExe2x80x9d.
A drawback of presently known machines for the making of cigarettes or the like is that they are too complex, too bulky or that they fail to produce tobacco streams which are of uniform quality, i.e., which can be converted into rod-shaped smokers"" products meeting the highest and strictest requirements regarding the composition of their fillers such as the absence of ribs, the absence of unsatisfactory ribs, the absence of impurities, proper distribution of tobacco dust, uniform density, dense ends of the fillers at the lighted ends of cigarettes, cigars or cigarillos, absence of punctures (such as those caused by tobacco ribs) and the like. In other words, those parameters of the rod-like filler or fillers which are normally monitored by testing equipment in a cigarette making, cigar making or cigarillo making machine preparatory to and during advancement toward the conveyor(s) which gathers or gather the acceptable constituents of one or more streams of smokable material into one or more surplus-containing rod-like fillers should meet the strictest requirements for extended periods of time to thus reduce the percentage of rejects. This involves satisfactory sifting of the air-entrained tobacco shredxe2x80x94tobacco rib mixture preparatory to and during advancement toward the conveyor(s) which gathers or gather the acceptable constituents of one or more streams into one or more surplus-containing streams. Satisfactory regulation of the flow of air in the distributor is of particular importance in order to ensure segregation of any and all or of unacceptable ribs and/or other impurities and to otherwise manipulate the flow or flows of tobacco particles toward the trimming or surplus removing station(s).
An object of the instant invention is to provide a novel and improved distributor or hopper for use in or in conjunction with machines for making cigarettes or other smokable material containing commodities.
Another object of our invention is to provide a novel and improved tobacco conveying and classifying arrangement for use in the distributors of cigarette making and other machines for the conversion of mixtures of comminuted tobacco leaves into smokers"" products.
A further object of this invention is to provide a novel and improved air circulating and recirculating arrangement for use in the distributors of cigarette making and analogous machines.
An additional object of the present invention is to provide a distributor which constitutes an improvement over and a further development of the distributors disclosed in U.S. Pat. No. 5,645,086 to Brand et al.
Still another object of this invention is to provide a novel and improved method of sifting, conveying and/or otherwise manipulating mixtures of tobacco shreds, tobacco ribs, tobacco dust and impurities in the distributor of a machine for making cigarettes or other smokers"" products.
A further object of this invention is to provide a novel and improved method and a novel and improved combination of parts for segregating high-quality fragments of tobacco leaves, reconstituted tobacco and/or artificial tobacco from lower-quality fragments and/or impurities.
Another object of the invention is to provide a machine for making cigarettes or other smokers"" products which includes or is associated with a distributor or hopper embodying the above-enumerated novel features and exhibiting important advantages over presently known machines and their distributors.
An additional object of our present invention is to provide a compact and relatively inexpensive long-lasting tobacco processing apparatus which can be combined with or incorporated in available machines for making cigarettes or other rod-shaped smokers"" products.
Still another object of the present invention is to provide novel and improved means for sifting mixtures of high-quality or higher-quality and low-quality or lower-quality fragments of tobacco leaves, artificial tobacco and/or substitute tobacco in or ahead of cigarette making or analogous machines for the mass production of smokers"" products.
A further object of the invention is to provide a distributor which can produce and deliver one or more unchanging or substantially unchanging streams or flows of high-quality particles of natural, substitute and/or reconstituted tobacco for long periods of time.
Another object of our invention is to provide a distributor or hopper which can be utilized with advantage in conjunction with or in machines for simultaneously making and processing several streams or flows of homogeneous comminuted smokable material.
One feature of the present invention resides in the provision of an apparatus known as distributor or hopper and serving to build at least one rod-like filler containing at least one constituent (e.g., shreds of tobacco leaf laminae) of a mixture of smokable particulate material (such mixture can contain shreds, fragments of tobacco ribs, so-called eyes and tobacco dust) and being pneumatically delivered to at least one foraminous conveyor (particularly to the underside of the at least substantially horizontal lower reach or stretch of an air-permeable belt conveyor, the lower reach being advanced below at least one suction chamber which attracts the at least one constituent of the mixture to the underside of the lower reach).
The improved apparatus comprises means for supplying the at least one constituent to the foraminous conveyor (such supplying means preferably comprises at least one guide having a preferably concave surface defining a path for advancement of the at least one constituent to the foraminous conveyor), a metering device which is arranged to supply the at least one constituent of the mixture into the aforementioned path, and a sifter which is arranged to supply the at least one constituent and air to the metering device.
The metering device can include an upright duct and the sifter preferably includes an at least substantially zig-zag-shaped sifter having a plurality of stages including a lowermost stage. Such zig-zag sifter preferably further includes or cooperates with a pneumatic follow-up sifter which is or can be installed beneath the lowermost stage of the zig-zag sifter. The follow-up sifter can include an air box and a sieve which separates the air box from the lowermost stage of the zig-zag sifter. Such apparatus can further comprise an air circulating system which is connected with the follow-up sifter and discharges air into the aforementioned path leading from the guide or guides to the foraminous conveyor(s).
The duct of the metering device can be provided with a vibrating outlet which is arranged to discharge the at least one constituent of the mixture for delivery into the aforementioned path, and at least one rotary withdrawing member which serves to direct the at least one constituent from the vibrating outlet into the path. Such apparatus preferably further comprises an air separator which is interposed between the sifter and the inlet of the duct. The separator can include or constitute a Coanda separator. As already mentioned hereinabove, the just described apparatus can comprise an air circulating system including a frequency-regulated transverse air stream generating blower; the sifter and the Coanda separator can constitute integral parts of such air circulating system. The latter is arranged to direct at least one stream of air in a predetermined direction and can further include an air bypass which is disposed downstream of the blower, as seen in the predetermined direction. Still further, the air circulating system can comprise an air-conveying elbow having radially inner and radially outer portions, and the air bypass preferably receives air from the radially outer portion of such elbow.
The zig-zag sifter can further comprise a rotary picker roller disposed opposite the follow-up sifter of the zig-zag sifter and serving to break up coherent accumulations, such as clumps (if any) of the mixture of smokable particulate materials which have entered the zig-zag sifter.
The metering device is preferably arranged to supply the at least one constituent of the mixture with a surplus which is removed at the at least one foraminous conveyor (e.g., in a manner as disclosed in the aforementioned U.S. Pat. No. 4,893,640 to Heitmann et al.). Such apparatus preferably further comprises a pneumatic return conduit which delivers the removed surplus into or close to the uppermost stage or section of the zig-zag sifter. The aforesaid air circulating system in the just discussed embodiment of the improved apparatus can further include an elbow and the pneumatic return conduit can receive air from the radially inner portion of the elbow.
The apparatus can further comprise a reservoir for the mixture of several constituents and a duct which leads from the reservoir downwardly to a median stage or section of the zig-zag sifter. A carded feeding roller is preferably provided to supply a continuous flow or batches of mixture from the reservoir into the inlet of the duct.
The rotational speed of the blower of the aforementioned air circulating system can be regulated in dependency upon changes of the pressure differential which exists between the uppermost and lowermost stages of the zig-zag sifter. The means for regulating the rotational speed of the blower can comprise a first signal generating pressure sensor at the level of or at a level above the uppermost stage of the zig-zag sifter, a second signal generating pressure sensor which is installed at the level of the lowermost stage of the zig-zag sifter, and means for comparing the signals from such sensors and for transmitting appropriate signals to the motor or another suitable prime mover which drives the blower.
The quantity of at least one constituent of smokable material in the metering device can be monitored by a suitable sensor which generates signals serving to regulate the rate at which the mixture of smokable constituents is being fed from the aforementioned magazine into the sifter (such as the aforementioned zig-zag sifter).
In accordance with a modification, and primarily in order to achieve savings in space, the means for supplying the mixture of smokable constituents to the zig-zag sifter comprises a so-called elevator conveyor which can include an endless belt or chain and rungs which transport batches of mixture from the magazine into the zig-zag sifter. The arrangement is preferably such that the elevator conveyor supplies the mixture into the zig-zag sifter at a level above the median portion of the latter. The metering device of such apparatus is or can be arranged to supply the at least one constituent with a surplus which is removed at the at least one foraminous conveyor; the means for returning the surplus to the magazine preferably includes one or more feed screws. Still further, such apparatus can comprise means for monitoring the quantity of the at least one constituent in the metering device and suitable means for driving the elevator conveyor at a speed which is a function of the monitored quantity of the at least one constituent in the metering device.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and the modes of assembling and operating the same, together with numerous additional important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawing.